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[PATCH] i386: fix dubious segment register clear in cpu_init()

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Fix a very dubious piece of code in
arch/i386/kernel/cpu/common.c:cpu_init().  This clears out %fs and
%gs, but clobbers %eax in the process without telling gcc.  It turns
out that gcc happens to be not using %eax at that point anyway so it
doesn't matter much, but it looks like a bomb waiting to go off.

This does end up saving an instruction, because gcc wants %eax==0 for
the set_debugreg()s below.

Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andi Kleen <ak@suse.de>
This commit is contained in:
Jeremy Fitzhardinge 2006-09-26 10:52:34 +02:00 committed by Andi Kleen
parent 3b8d1fe0f2
commit 5758d5dfef
1 changed files with 1 additions and 1 deletions
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2
arch/i386/kernel/cpu/common.c
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@ -675,7 +675,7 @@ old_gdt:
#endif
/* Clear %fs and %gs. */
asm volatile ("xorl %eax, %eax; movl %eax, %fs; movl %eax, %gs");
asm volatile ("movl %0, %%fs; movl %0, %%gs" : : "r" (0));
/* Clear all 6 debug registers: */
set_debugreg(0, 0);